1952 Theatre Catalog, 10th Edition, Page 28 (xxviii)

1952 Theatre Catalog, 10th Edition, Page 28

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FIG. 23-The observation port (lelt) should be closed with a good grade of plate glass. set in a lmme
which will permit easy cleaning on both sides. If glass is tilted from the perpendicular it will overcome
reflections and improve the critical View oi the watching projectionist. The projection port (right)
should enioy a good grade of optical glass set in a frame that can be adjusted to the proiection angle.
It also should be easily removed {or daily cleaning. Recommended installation methods can he noted.

Portholes

Two portholes are required for each
projection machine, one for observation and the other for the light beam,
and, while the size of these ports is
sometimes set by local regulations, the
average and sufficient size is 10 inches
square for the projection port and 10
by 12 inches for the observation openings. Both ports should be incloscd with
glass in adjustable frames. A high
grade of optical glass should be used
in the projection opening, and this glass
should be in a frame which can be adjusted to be normal to the projection
angle. A good grade of plate glass
should be used for closing the observae
tion ports, and the glass should be sot
in a frame that may be easily adjusted
to facilitate cleaning on both sides. The
operator will have a better view out of the observation port if the glass is tilted
slightly to overcome reflections from
house lights and tho scrcen.

With spotlights in the booth, portholcs to accommodate them will have

XXVIII

to be much larger than the others in
order to allow the spots to pivot horizontally and vertically to cover the entire stage. Spotlight openings should be
closed with polished wire glass set in
removable stops. As this opening is necessarily large, the glass should be set
in a frame with metal stops, without
provision for hinging.

Specially shaped openings are required for effect machines and stcrcopticons, and should this equipment be
contemplated the manufacturer should
be consulted so that booth openings can
be tailored to specifications.

It is mandatory that projection and
observation openings be protected on
tho projection room side with safety
shutters of steel or transite board which
will close automatically if fire breaks
out anywhere in the booth. A system of
fusible links and cords holds those shutters open. A metal shaft is installed
on ball-bearing hangers above the
openings and extends the full length of the front wall of the booth. The shaft

has pegs inserted over the center of
each opening from which the safety
shutter is hung by means of a fusible
link or a cord. Each cord is looped OVer
the proper peg on the shaft, and on one
end of the shaft is a counterweighted
arm held in position through an arrangement of cords and pulleys with the cord running over the center of the
machines and broken with fusible links
at each machine. When the cord is severed, the counterweight drops, and the
loops slip off the pegs, allowing all
safety shutters to fall into the closed
position. Provision for manually dropping the shutters should also be made
at each booth exit. Counterweights
should be placed on the cords operating
safety shutters on large booth openings.

Electrical Ou'l'lel's

If new sound and projection equipment is to be installed, wiring diagrams
should be obtained from the manufacturer of the equipment. Conventional
outlets Should be installed in the front
wall of each projection booth, at each
machine location for connecting trouble
lights and soldering irons, if these are
not built into the equipment,

Mechanical and gravity ventilation is
necessary in the booth, with one system
directly connected to the lamphouses.

Even though local codes do not always compel the inclusion of two exits
at opposite ends of the booth, these
should be provide for the safety of the
projectionists.

THE STAGE

Sl'age Floor

If the floor of the stage is in bad
condition it should be repaired of
course. Old wooden floors may be, covered with dark, dull finish linoleum, or
stained a dark color to prevent reflection of light from the projectors. If the
floor is in an irreparable condition, it
should be replaced with a concrete
structure.

If it is decided to tear the stago down
to a platform three or four foot above
the orchestra floor, this platform can
greatly add to the beauty of the auditorium if properly treated. Draperies of
appropriate color and design, hung from the proscenium arch and closed to the
picture help make the platform the focal point of the house. The scrcon curtain should be hung on a track, and
opened and closed by means of an electric curtain machine controlled by push
buttons on the stage and in tho projection booth.

Footlights, borderlights, or floods in
the auditorium ceiling also operated
from the projection booth, should be
planned for lighting the platform and
for illuminating the screen curtain and
stage set at the opening and closing
pcriods. A system of slowly revolving
colorod lights may be used to play a
dazzling cascade of artistic effects on the stage curtain between shows.

It. should be pointed out that the stage
may not be used as such in some localities because of agreements with the local stagchandsy union. Before any alteration which contemplates future uses of the stage is started, it is a good idea to
consult the local stagehandsl union.